Maraging is a series of martensitic aged steels with a nickel content of 18% and enhanced performance by adding cobalt. The steel grades in this series have excellent mechanical properties, processing performance, and heat treatment performance.
Maraging 300 is an ultra-high strength steel based on carbon free (or micro carbon) martensite, which can produce intermetallic compound precipitation hardening during aging. Unlike traditional high-strength steel, it does not require carbon and relies on the dispersion and precipitation of intermetallic compounds for strengthening. This gives it some unique properties: high strength and toughness, low hardening index, good formability, simple heat treatment process, almost no deformation during aging, and good welding performance. Therefore, martensitic aging steel has been widely used in sectors that require this characteristic.
Maraging 300 Steel Production Process:
The main production processes include smelting, hot processing, cold processing, welding, heat treatment, and surface treatment.
Smelting:
Generally, a dual vacuum smelting process is adopted, which includes vacuum induction furnace melting and vacuum consumable furnace remelting. For steel grades with strength levels below 1500MPa, non vacuum smelting or non vacuum smelting with electric slag remelting process can be used. However, for high-strength grade and important steel grades, the dual vacuum smelting process must be adopted. During vacuum self consumption remelting, the current and molten pool temperature should be strictly controlled to avoid severe dendritic segregation of the steel ingot.
Maraging 300 Steel Heat Treat:
The simple heat treatment process is another important advantage of martensitic aging steel. Maraging 300 should undergo solid solution treatment before cold processing and aging strengthening after hot processing. The purpose is to dissolve the remaining precipitate after hot processing; Dissolve the matrix with sufficient strengthening elements; And obtain a uniform high dislocation density full martensitic structure. The solid solution temperature is usually 820-840 ℃, and the solid solution time is 1 hour per 25 ram thickness. After the solid solution, it is air-cooled, and the cooling rate has little effect on the structure and properties. The high strength of martensitic aging steel is obtained through aging treatment. The aging temperature is generally 480 ℃, and for high-strength steel grades, 510 ℃ can be used. The aging time is 3-6 hours, and air cooling is required after aging. After aging, a large number of dispersed and ultra microscopic intermetallic compound particles precipitate on the martensitic matrix, resulting in a doubling of the material's strength and minimal toughness loss.
